I assume you're referring to
this. That is nothing at all like what we were talking about. Apple's Small Business service is more akin to a tech services consultancy that manages software and device deployment and security and has nothing to do with expedited on-site hardware repairs. It is more akin to something like a simplified Microsoft Entra device management with some mobile device management added.
The closest thing that Apple offers to Dell's ProSupport plans is
AppleCare for Enterprise which has a minimum enrolment requirement of 200 devices.
Since we're talking about iMacs in this thread, sure. But many laptops still use hinge designs that can be quite easily replaced on-site with little more than a screwdriver. I find it hard to believe that a tech who carries around laptop motherboards and outer shells would not also carry around commonly-used displays.
The definition of "corp" customers being the key thing here. Dell will offer "corp" service to anyone who buy a business-level machine with a high-enough ProSupport plan. Including my 30 employee firm and OP's single-person (presumably) business.
I suspect you have a lot more personal experience with HP and Lenovo than you do with Dell. I have no experience with HP or Lenovo so I'll take your word for it.
I guess you also don't use a laptop, then?
Use what works best for you.